Between 2000 and last year, the neo-soul great all but vanished from the scene, apart from a well-publicized 2005 car crash. His latest disappearing act is now underway, following today's sudden announcement that his Saturday show here at Humphreys Concerts by the Bay has been cancelled because of a "medical emergency." Tickets can be refunded at point of purchase.

Just what his medical emergency might be has not yet been disclosed. But D'Angelo's Tuesday concert in Minneapolis has also been cancelled, along with his Wednesday show in Chicago. No word yet on whether his scheduled Friday performance at San Francisco's Outside Lands' festival will go on as planned, but we wouldn't bet on it, as none of his scheduled August concerts, starting with an Aug. 1 date in New York with Roots' leader (and lontime D'Angelo collaborator) ?uestlove, appear to have actually taken place.

D'Angelo's 1995 debut “Brown Sugar” and its 2000 follow-up “Voodoo” rank as two of the finest neo-soul albums of the past 20 years. Both are vibrant classics that expertly fused classic R&B song craft with fresh hip-hop swagger.

But between 2001 and last year, the man born Michael D’Angelo Archer all but vanished. After repeated false starts (a purported 2010 album with Amy Winehouse producer Mark Ronson has yet to materialize), D’Angelo returned to the concert stage last year, teaming with ?uestlove and an all-star band to perform at last summer's Bonnaroo festival in Tennessee. More dates followed.

D'Angelo's now-canceled tour teamed him with with a nine-piece band that included ace bassist Pino Palladino and former The Time guitarist Jesse Johnson. Here’s hoping he has a quick and full recovery.